174 BASIC BODIES. 



known, on which we can even hazard a conjecture regarding the 

 conditions under which it is formed. 



ALLANTOIXE. C 8 H 5 N 4 O 5 .IIO. 



Chemical Relations. 



Properties. This body forms colourless, hard prisms, of therhoin- 

 bohedric primitive form, which have a strong vitreous brilliance; it is 

 devoid of smell and taste, dissolves in 160 parts of cold water, 

 and more easily in hot water ; it crystallises from its hot alcoholic 

 solution, is insoluble in ether, is unaffected by exposure to the 

 atmosphere, does not redden litmus, and chars, when heated, 

 without fusing. It dissolves in solutions of the caustic alkalies and 

 their carbonates, when these are warmed, but crystallises from them 

 in an unchanged condition as they cool ; it is decomposed by con- 

 centrated caustic alkalies, taking up water and resolving itself into 

 oxalic acid and ammonia (C 8 H 5 N 4 O 5 + 7HO=r4H 3 N + C 2 O 3 ) ; 

 when boiled with concentrated sulphuric acid, it also takes up 

 water, developing carbonic acid and carbonic oxide, and leaving 

 sulphate of ammonia. On warming it with nitric acid (of 1*2 to 

 1'4 specific gravity,) it becomes decomposed into urea and allantoic 

 acid, (3 atoms of allantoine, taking up 7 atoms of water, yield 2 

 atoms of urea and 2 atoms of allantoic acid, for C. 24 H 15 N 12 O 5 + 

 7HO= C 4 H 8 N 4 4 + C 20 H 14 N 8 18 .) 



Allantoine enters into combination with the oxides of lead and 

 silver. 



Composition. Liebig and Wb'hler* were the first who accurately 

 determined the composition of crystallised allantoine, and they 

 deduced the above formula from its silver-compound, according to 

 which it consists of : 



Carbon 8 atoms .... 30'38 



Hydrogen 5 .... 3*16 



Nitrogen 4 .... 35-44 



Oxygen 5 .... 25'32 



Water 1 .... 570 



100-00 



The atomic weight of the hypothetical dry allantoine= 1862.5. 

 This body cannot be reckoned amongst the organic bases, since 

 it does not combine with any acid ; but from the analogy of its 



* Pogg. Ann. Bd. 31, S. 501. 



